A dead battery is one of the most common ways a car strands you, but a set of jumper cables and a running vehicle can get you moving again. Connecting the cables in the right order is the key to doing it safely.
What you'll need
- Jumper cables
- A second working vehicle
- Gloves and eye protection (optional)
Step by step
- Position the vehiclesPark the working car close enough for the cables to reach, but not touching the dead one. Put both cars in park or neutral, set the parking brakes, and turn off both engines.
- Connect the positive cablesClamp one red clip to the positive terminal of the dead battery, marked with a plus sign, and the other red clip to the positive terminal of the good battery.
- Connect the ground lastClamp one black clip to the negative terminal of the good battery, then clamp the other black clip to an unpainted metal bolt or bracket on the dead car's engine, away from the battery. This grounding point reduces spark risk near the battery.
- Start the working carStart the good vehicle and let it run for a few minutes. This sends charge into the dead battery before you try to start it.
- Start the dead carTry to start the car with the dead battery. If it does not turn over, wait a few more minutes and try again.
- Remove the cables in reverseOnce it is running, disconnect the cables in the opposite order you attached them: the black ground clamp, the black clamp on the good battery, then both red clamps. Keep the running car going and drive it a while to recharge.
Handy tips
- Drive the jumped car for at least 20 to 30 minutes so the alternator can recharge the battery.
- Keep a set of jumper cables or a portable jump pack in your trunk for emergencies.
- Make sure the clamps never touch each other while any end is connected to a battery.
Heads up
- Connect and disconnect the cables in the correct order, since mistakes can spark near the battery or damage electronics.
- Do not attempt a jump-start if the battery is cracked, leaking, or visibly damaged, as it could rupture.
- Keep the cables clear of moving engine parts like belts and fans.
FAQ
Why attach the last clamp to metal instead of the battery?
Grounding to an unpainted metal part away from the battery keeps any spark from igniting the small amount of hydrogen gas a battery can give off, making the connection safer.
My car still will not start after a jump. What now?
Recheck that the clamps are tight and on the right terminals, then wait a few more minutes and try again. If it still fails, the battery may be dead beyond a jump or another part has failed.
How long should I drive after jump-starting?
At least 20 to 30 minutes of driving lets the alternator recharge the battery. If it dies again after shutting off, the battery likely needs replacing.